U.S. patent number 10,263,589 [Application Number 14/889,523] was granted by the patent office on 2019-04-16 for noise filter.
This patent grant is currently assigned to Mitsubishi Electric Corporation. The grantee listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Kenji Hirose, Mao Kawamura, Mamoru Takikita, Yusuke Tsubaki.
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United States Patent |
10,263,589 |
Tsubaki , et al. |
April 16, 2019 |
Noise filter
Abstract
A noise filter is provided with a filter circuit including a
first condenser and a second condenser; the first condenser and the
second condenser are connected in parallel with each other by a
first wiring lead for connecting one terminal of the first
condenser with one terminal of the second condenser and a second
wiring lead for connecting the other terminal of the first
condenser with the other terminal of the second condenser; the
first wiring lead and the second wiring lead are arranged in such a
way as to intersect each other odd-number times.
Inventors: |
Tsubaki; Yusuke (Tokyo,
JP), Kawamura; Mao (Tokyo, JP), Takikita;
Mamoru (Tokyo, JP), Hirose; Kenji (Tokyo,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
N/A |
JP |
|
|
Assignee: |
Mitsubishi Electric Corporation
(Tokyo, JP)
|
Family
ID: |
52688353 |
Appl.
No.: |
14/889,523 |
Filed: |
September 17, 2013 |
PCT
Filed: |
September 17, 2013 |
PCT No.: |
PCT/JP2013/075004 |
371(c)(1),(2),(4) Date: |
November 06, 2015 |
PCT
Pub. No.: |
WO2015/040665 |
PCT
Pub. Date: |
March 26, 2015 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20160126919 A1 |
May 5, 2016 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H03H
7/427 (20130101); H01G 4/40 (20130101); H03H
7/0115 (20130101); H01G 4/35 (20130101); H04B
3/26 (20130101); H03H 2001/0035 (20130101); H02M
1/126 (20130101); H02M 1/12 (20130101); H02J
3/01 (20130101) |
Current International
Class: |
H03H
7/01 (20060101); H01G 4/40 (20060101); H01G
4/35 (20060101); H03H 7/42 (20060101); H04B
3/26 (20060101); H02J 3/01 (20060101); H02M
1/12 (20060101); H03H 1/00 (20060101) |
Field of
Search: |
;333/12,167,175,181,184
;336/90,192 ;361/275.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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|
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2466839 |
|
Dec 2001 |
|
CN |
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1 006 673 |
|
Jun 2000 |
|
EP |
|
5-53320 |
|
Jul 1993 |
|
JP |
|
06-77756 |
|
Mar 1994 |
|
JP |
|
07-226331 |
|
Aug 1995 |
|
JP |
|
2000-259048 |
|
Sep 2000 |
|
JP |
|
2000-299615 |
|
Oct 2000 |
|
JP |
|
2000-315930 |
|
Nov 2000 |
|
JP |
|
2001-023849 |
|
Jan 2001 |
|
JP |
|
2002-164245 |
|
Jun 2002 |
|
JP |
|
2007-124125 |
|
May 2007 |
|
JP |
|
2011-223314 |
|
Nov 2011 |
|
JP |
|
Other References
Panasonic data sheet for Plastic film capacitors, ECQE series, Apr.
2013. cited by examiner .
English Translation of JP Publication No. 2000-315930, published
Nov. 14, 2000. cited by applicant .
English Translation of JP Publication No. 2000-299615, published
Oct. 24, 2000. cited by applicant .
English Translation of JP Publication No. 2000-259048, published
Sep. 22, 2000. cited by applicant .
English Translation of JP Publication No. 2002-164245, published
Jun. 7, 2002. cited by applicant .
English Translation of JP Publication No. 2011-223314, published
Nov. 4, 2011. cited by applicant .
English Translation of JP Publication No. 7-226331, published Aug.
22, 1995. cited by applicant .
English Translation of JP Publication No. 6-077756, published Mar.
18, 1994. cited by applicant .
Communication dated Nov. 22, 2016 from the Japanese Patent Office
in counterpart Application No. 2015-537440. cited by applicant
.
Shuo Wang et al., "Improvement of EMI Filter Performance With
Parasitic Coupling Cancellation", IEEE Transactions on Power
Electronics, Sep. 2005, pp. 96-103, vol. 20, No. 5. cited by
applicant .
International Search Report of PCT/JP2013/075004 dated Nov. 12,
2013 [PCT/ISA/210]. cited by applicant .
Communication dated Jun. 9, 2017, from the European Patent Office
in counterpart European Application No. 13893859.2. cited by
applicant .
Communication dated Jun. 1, 2017, from the Chinese Patent Office in
counterpart Application No. 201380079626.X. cited by applicant
.
Communication dated Oct. 9, 2017 from the State Intellectual
Property Office of the P.R.C. in counterpart Chinese application
No. 201380079626.X. cited by applicant .
Communication dated May 22, 2018 from the European Patent Office in
counterpart application No. 13893859.2. cited by applicant .
Communication dated May 3, 2018, issued by the State Intellectual
Property Office of the P.R.C. in counterpart Chinese application
No. 201380079626.X. cited by applicant .
Communication dated Dec. 3, 2018 from the European Patent Office in
application No. 13893859.2. cited by applicant .
Chinese Office Action dated Feb. 13, 2019 in Patent Application No.
201380079626.X. cited by applicant.
|
Primary Examiner: Lee; Benny T
Assistant Examiner: Rahman; Hafizur
Attorney, Agent or Firm: Sughrue Mion, PLLC Turner; Richard
C.
Claims
The invention claimed is:
1. A noise filter comprising: a first film condenser; and a second
film condenser, wherein the first film condenser and the second
film condenser are arranged at a distance in which the first film
condenser and the second film condenser are magnetically coupled
with each other of an inductive nature and are connected in
parallel with each other by a first wiring lead, which connects a
first terminal of the first film condenser directly with a first
terminal of the second film condenser, and by a second wiring lead,
which connects a second terminal of the first film condenser
directly with a second terminal of the second film condenser,
without any other circuit component connected between the first
film condenser and the second film condenser, and wherein the first
wiring lead and the second wiring lead are arranged in such a way
as to intersect each other an odd number of times.
2. The noise filter according to claim 1, wherein each of the first
and second wiring leads is formed of a bus bar.
3. The noise filter according to claim 1, wherein each of the first
and second wiring leads is formed of a conductive wire.
4. A noise filter comprising: three or more film condensers
including a first film condenser and a second film condenser,
wherein the first film condenser and the second film condenser are
arranged at a distance in which the first film condenser and the
second film condenser are magnetically coupled with each other of
an inductive nature and are connected in parallel with each other
by a first wiring lead, which connects a first terminal of the
first film condenser directly with a first terminal of the second
film condenser, and by a second wiring lead, which connects a
second terminal of the first film condenser directly with a second
terminal of the second film condenser, without any other circuit
component connected between the first film condenser and the second
film condenser, wherein each of the three or more film condensers
other than the first film condenser and the second film condenser
is connected in parallel with the first film condenser and the
second film condenser, and wherein the first wiring lead and the
second wiring lead are arranged in such a way as to intersect each
other an odd number of times.
5. The noise filter according to claim 4, wherein the first and
second terminals of the first film condenser are connected to a
power source, and wherein the first and second terminals of the
second film condenser are connected to an electric apparatus.
6. The noise filter according to claim 4, wherein the first and
second terminals of the first film condenser are connected to an
electric apparatus, and wherein the first and second terminals of
the second film condenser are connected to a power source.
7. The noise filter according to claim 4, wherein the first and
second terminals of the first film condenser are connected to an
electric apparatus, and wherein the first and second terminals of
the second film condenser are connected to a load of an electric
apparatus.
8. The noise filter according to claim 4, wherein the first and
second terminals of the first film condenser are connected to a
load of an electric apparatus, and wherein the first and second
terminals of the second film condenser are connected to an electric
apparatus.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a National Stage of International Application
No. PCT/JP2013/075004, filed Sep. 17, 2013, the contents of which
are incorporated herein by reference in its entirety.
TECHNICAL FIELD
The present invention relates to a noise filter.
BACKGROUND ART
As a conventional noise filter, a technology disclosed in
Non-Patent Document 1 is known. This conventional noise filter is
configured with two coils, two across-the-line condensers
(hereinafter, referred to as an X condenser); the two coils are
connected between the respective one terminals and the respective
other terminals of the two X condensers; this noise filter is
configured in such a way that there is provided a path through
which an electric current having a direction opposite to the
direction of an electric current flowing in the one of the two X
condensers flows in the other one. In the conventional noise filter
configured in such a manner as described above, because when an
electric current flows in the one X condenser, an
opposite-direction electric current flows in another path;
therefore, magnetic fluxes generated by the electric currents
flowing the respective paths are cancelled each other, so that
magnetic coupling with the other X condenser is suppressed. As a
result, the normal-mode attenuation amount in the noise filter is
substantially improved.
Patent Document 1 discloses, as a circuit technology that can be
utilized in a filter, a method of suppressing magnetic coupling
between condensers by the way in which the respective condensers
are arranged. In this method, a plurality of condensers that are
connected in parallel with one another are arranged in such a way
that the vector of an electric current flowing in one of the
plurality of condensers is not parallel to the vector of an
electric current flowing in another (adjacent) condenser, so that
magnetic coupling between the condensers is suppressed.
PRIOR ART REFERENCE
Patent Document
[Patent Document 1] Japanese Patent Application Laid-Open No.
2001-23849
Non-Patent Document
[Non-Patent Document] Improvement of EMI Filter Performance With
parasitic Coupling Cancellation (IEEE TRANSACTIONS ON POWER
ELECTRONICS, VOL. 20, NO. 5, Sep. 2005)
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
However, in the conventional noise filter disclosed in Non-Patent
Document 1, there has been a problem that no typical X condenser
cannot be utilized and it is required to utilize an X condenser
having a special structure. Moreover, in the circuit technology,
disclosed in Patent Document 1, that can be utilized in a filter,
there has been a problem that because the arrangement of condensers
restricts the arrangement of circuit components and wiring leads,
the circuit area is upsized in proportion to the number of
condensers.
The present invention has been implemented in order to solve the
foregoing problems in the conventional noise filters; the objective
thereof is to provide a noise filter in which typical condensers
can be utilized and magnetic coupling between the condensers can be
suppressed regardless of the method of arranging the
condensers.
Means for Solving the Problems
A noise filter according to the present invention includes a first
film condenser and a second film condenser and is characterized in
that the first film condenser and the second film condenser are
arranged at a distance in which they are magnetically coupled with
each other and are connected in parallel with each other by a first
wiring lead for connecting one terminal of the first film condenser
with one terminal of the second film condenser and a second wiring
lead for connecting the other terminal of the first film condenser
with the other terminal of the second film condenser, and in that
the first wiring lead and the second wiring lead are arranged in
such a way as to intersect each other odd-number times.
Moreover, a noise filter according to the present invention
includes a first film condenser, a second film condenser, a first
coil, and a second coil and is characterized in that the first film
condenser and the second film condenser are arranged at a distance
in which they are magnetically coupled with each other, in that
there are provided a first wiring lead for connecting one terminal
of the first film condenser with one terminal of the second coil
and a second wiring lead for connecting the other terminal of the
first film condenser with one terminal of the first coil, in that
one terminal of the second film condenser is connected with the
other terminal of the second coil, in that the other terminal of
the second film condenser is connected with the other terminal of
the first coil, and in that the first wiring lead and the second
wiring lead are arranged in such a way as to intersect each other
odd-number times.
Furthermore, a noise filter according to the present invention is
provided with three or more film condensers including a first film
condenser and a second film condenser, and is characterized in that
the first film condenser and the second film condenser are arranged
at a distance in which they are magnetically coupled with each
other and are connected in parallel with each other by a first
wiring lead for connecting one terminal of the first film condenser
with one terminal of the second film condenser and a second wiring
lead for connecting the other terminal of the first film condenser
with the other terminal of the second film condenser, in that each
of the film condensers other than the first film condenser and the
second film condenser is connected in parallel with the first film
condenser and the second film condenser, and in that the first
wiring lead and the second wiring lead are arranged in such a way
as to intersect each other odd-number times.
Moreover, a noise filter according to the present invention is
provided with three or more film condensers including a first film
condenser and a second film condenser, a first coil, and a second
coil, and is characterized in that the first film condenser and the
second film condenser are arranged at a distance in which they are
magnetically coupled with each other, in that there are provided a
first wiring lead for connecting one terminal of the first film
condenser with one terminal of the second coil and a second wiring
lead for connecting the other terminal of the first film condenser
with one terminal of the first coil, in that one terminal of the
second film condenser is connected with the other terminal of the
second coil, in that the other terminal of the second film
condenser is connected with the other terminal of the first coil,
in that each of the film condensers other than the first film
condenser and the second film condenser is connected in parallel
with the first film condenser and the second film condenser, and in
that at least one pair of wiring leads among the first and second
wiring leads and respective pairs of wiring leads for connecting
the film condensers in parallel with each other intersect each
other odd-number times.
Furthermore, a noise filter according to the present invention
includes a first film condenser, a second film condenser, a third
film condenser, a first coil, a second coil, a third coil, and a
fourth coil, and is characterized in that the first film condenser,
the second film condenser, and the third film condenser are
arranged at distances in which they are magnetically coupled with
one another, in that there are provided a first wiring lead for
connecting one terminal of the first film condenser with one
terminal of the first coil, a second wiring lead for connecting the
other terminal of the first film condenser with one terminal of the
second coil, a third wiring lead for connecting one terminal of the
third film condenser with the other terminal of the first coil, a
fourth wiring lead for connecting the other terminal of the third
film condenser with the other terminal of the second coil, a fifth
wiring lead for connecting one terminal of the third film condenser
with one terminal of the third coil, a sixth wiring lead for
connecting the other terminal of the third film condenser with one
terminal of the fourth coil, a seventh wiring lead for connecting
one terminal of the second film condenser with the other terminal
of the third coil, and an eighth wiring lead for connecting the
other terminal of the second film condenser with the other terminal
of the fourth coil, and in that in at least one of the respective
wiring pairs between the first wiring lead and the second wiring
lead, the third wiring lead and the fourth wiring lead, the fifth
wiring lead and the sixth wiring lead, and the seventh wiring lead
and the eighth wiring lead, the wiring leads intersect each other
odd-number times.
Advantage of the Invention
A noise filter according to the present invention makes it possible
to suppress magnetic coupling between condensers; therefore, the
normal-mode attenuation characteristics of the noise filter can be
improved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram for explaining a noise filter according
to Embodiment 1 of the present invention;
FIG. 2 is a perspective view schematically illustrating a noise
filter according to Embodiment 1 of the present invention;
FIG. 3 is a circuit diagram for explaining a conventional noise
filter;
FIG. 4 is a perspective view schematically illustrating the
conventional noise filter;
FIG. 5 is an explanatory diagram representing current paths through
which normal-mode noise currents flow in X condensers in the
conventional noise filter;
FIG. 6 is a perspective view schematically illustrating the current
paths through which the normal-mode noise currents flow in the X
condensers and the magnetic fluxes generated by the normal-mode
currents in the conventional noise filter;
FIG. 7 is an explanatory diagram representing current paths through
which normal-mode noise currents flow in X condensers in the noise
filter according to Embodiment 1 of the present invention;
FIG. 8 is a perspective view schematically illustrating the current
paths through which the normal-mode noise currents flow in the X
condensers and the magnetic fluxes generated by the normal-mode
currents in the noise filter according to Embodiment 1 of the
present invention;
FIG. 9 is a circuit diagram for explaining a noise filter according
to Embodiment 2 of the present invention;
FIG. 10 is a perspective view schematically illustrating the noise
filter according to Embodiment 2 of the present invention;
FIG. 11 is an explanatory diagram representing current paths
through which normal-mode noise currents flow in X condensers in
the noise filter according to Embodiment 2 of the present
invention;
FIG. 12 is a perspective view schematically illustrating the
current paths through which the normal-mode noise currents flow in
the X condensers and the magnetic fluxes generated by the
normal-mode currents in the noise filter according to Embodiment 2
of the present invention;
FIG. 13 is a circuit diagram for explaining a noise filter
according to Embodiment 3 of the present invention;
FIG. 14 is a perspective view schematically illustrating the noise
filter according to Embodiment 3 of the present invention;
FIG. 15 is an explanatory diagram representing current paths
through which normal-mode noise currents flow in X condensers in
the noise filter according to Embodiment 3 of the present
invention;
FIG. 16 is a perspective view schematically illustrating the
current paths through which the normal-mode noise currents flow in
the X condensers and the magnetic fluxes generated by the
normal-mode currents in the noise filter according to Embodiment 3
of the present invention;
FIG. 17 is a characteristic graph representing the noise
attenuation characteristics of the noise filter according to
Embodiment 3 of the present invention;
FIG. 18 is a circuit diagram for explaining a noise filter
according to Embodiment 4 of the present invention;
FIG. 19 is a perspective view schematically illustrating the noise
filter according to Embodiment 4 of the present invention;
FIG. 20 is an explanatory diagram representing current paths
through which normal-mode noise currents flow in X condensers in
the noise filter according to Embodiment 4 of the present
invention;
FIG. 21 is a perspective view schematically illustrating the
current paths through which the normal-mode noise currents flow in
the X condensers and the magnetic fluxes generated by the
normal-mode currents in the noise filter according to Embodiment 4
of the present invention;
FIG. 22 is a circuit diagram for explaining a noise filter
according to Embodiment 5 of the present invention;
FIG. 23 is a perspective view schematically illustrating the noise
filter according to Embodiment 5 of the present invention;
FIG. 24 is a circuit diagram representing a noise filter that is a
variant example of the noise filter according to Embodiment 5 of
the present invention and in which two common-mode choke coils are
utilized; and
FIG. 25 is a perspective view schematically illustrating the noise
filter that is a variant example of the noise filter according to
Embodiment 5 of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
Hereinafter, a noise filter according to Embodiment 1 of the
present invention will be explained. FIG. 1 is a circuit diagram
for explaining a noise filter according to Embodiment 1 of the
present invention; FIG. 2 is a perspective view schematically
illustrating the noise filter according to Embodiment 1 of the
present invention. As illustrated in FIGS. 1 and 2, the noise
filter according to Embodiment 1 of the present invention is
provided with a first X condenser C1 as a first condenser and a
second X condenser C2 as a second condenser; the first X condenser
C1 and the second X condenser C2 are connected in parallel with
each other so as to form a filter circuit.
The noise filter configured in such a manner as described above is
inserted between a power source and an electric apparatus or
between the electric apparatus and a load of the electric
apparatus; the filter circuit attenuates noise generated by the
electric apparatus.
A first wiring lead 3 connects a terminal 1, one of the terminals
of the first X condenser C1, with a terminal 2, one of the
terminals of the second X condenser C2; a second wiring lead 6
connects a terminal 4, the other one of the terminals of the first
X condenser C1, with a terminal 5, the other one of the terminals
of the second X condenser C2. The first wiring lead 3 and the
second wiring lead 6 are arranged in such a way as to intersect
each other once. As described above, the noise filter configured in
such a manner is inserted between the power source and the electric
apparatus or between the electric apparatus and the load of the
electric apparatus so as to attenuate noise generated by the
electric apparatus. As illustrated in FIG. 2, the first and second
X condensers C1 and C2 each denote a metalized film condenser that
is utilized in a noise filter, in general, and are arranged in such
a way as to be parallel to each other. The number of intersections
between the first wiring lead 3 and the second wiring lead 6 is not
limited to one; it is only necessary to be an odd number.
Hereinafter, there will be explained a mechanism in which in the
noise filter according to Embodiment 1 of the present invention,
the first and second wiring leads 3 and 6 for connecting the first
and second X condensers C1 and C2 intersect each other once so that
the normal-mode attenuation characteristics of the noise filter is
improved.
At first, in order to understand the noise filter according to
Embodiment 1 of the present invention, a conventional noise filer
will be explained. FIG. 3 is a circuit diagram for explaining a
conventional noise filter; the conventional noise filter is
provided with the first X condenser C1 and the second X condenser
C2, which are the constituent elements the same as those provided
in the noise filter according to Embodiment 1 of the present
invention; however, the conventional noise filter is different from
the noise filter according to Embodiment 1 of the present invention
in that the wiring leads for connecting the first and second X
condensers C1 and C2 do not intersect each other. FIG. 4 is a
perspective view schematically illustrating the conventional noise
filter. It is assumed that in FIGS. 3 and 4, the noise filter is
connected between a power source and an electric apparatus, that
the first X condenser C1 is situated at the power source side and
the second X condenser C2 is situated at the electric apparatus
side, and that a noise source V1 exists in the electric
apparatus.
At first, the current path of a normal-mode noise current will be
explained. FIG. 5 is an explanatory diagram representing current
paths through which normal-mode noise currents flow in the X
condensers in the conventional noise filter; there is illustrated
current paths through which normal-mode noise currents generated by
the noise source V1 flow in the first and second X condensers C1
and C2. FIG. 6 is a perspective view schematically illustrating the
current paths through which the normal-mode noise currents flow in
the X condensers and the magnetic fluxes generated by the
normal-mode currents in the conventional noise filter.
In FIGS. 5 and 6, i1 denotes a normal-mode noise current that flows
in the first X condenser C1; i2 denotes a normal-mode noise current
that flows in the second X condenser C2. In FIG. 6, .PHI.1, .PHI.2,
.PHI.1', and .PHI.2' denote magnetic flux generated by the first X
condenser C1, magnetic flux generated by the second X condenser C2,
magnetic flux, out of the magnetic flux .PHI.1, that is interlinked
with the second X condenser C2, and magnetic flux, out of the
magnetic flux .PHI.2, that is interlinked with the first X
condenser C1, respectively.
In FIG. 6, the normal-mode noise currents i1 and i2 having the same
direction flow in the first X condenser C1 and the second X
condenser C2; therefore, the direction of the magnetic flux .PHI.1'
is the same as that of the magnetic flux .PHI.2' (in that
direction, the magnetic flux .PHI.1' and the magnetic flux .PHI.2'
strengthen each other). Accordingly, the first X condenser C1 and
the second X condenser C2 strongly couple with each other; thus,
the normal-mode attenuation characteristics of the noise filter is
deteriorated.
Next, the noise filter according to Embodiment 1 of the present
invention will be explained. FIG. 7 is an explanatory diagram
representing current paths through which normal-mode noise currents
flow in X condensers in the noise filter according to Embodiment 1
of the present invention; FIG. 8 is a perspective view
schematically illustrating the current paths through which the
normal-mode noise currents flow in the X condensers and the
magnetic fluxes generated by the normal-mode currents in the noise
filter according to Embodiment 1 of the present invention. As
illustrated in FIGS. 7 and 8, in the noise filter according to
Embodiment 1 of the present invention, because the respective
wiring leads for connecting the first X condenser C1 and the second
X condenser C2 intersect each other once, respective normal-mode
noise currents having opposite directions flow in the first X
condenser C1 and the second X condenser C2; thus, the direction of
the magnetic flux .PHI.1' is opposite to that of the magnetic flux
.PHI.2' (in those directions, the magnetic flux .PHI.1' and the
magnetic flux .PHI.2' cancel each other).
As described above, when the respective wiring leads for performing
connection between the X condensers intersect each other once, it
is made possible to suppress the magnetic coupling between the X
condensers; thus, the normal-mode attenuation effect of the noise
filter can be improved.
In Embodiment 1, the noise filter is configured in such a manner
that the respective wiring leads for connecting the first X
condenser C1 and the second X condenser C2 intersect each other
once; however, the number of intersection instances is not limited
thereto, and the respective wiring leads may intersect each other
once or more times as long as the number is odd. When the number of
intersection instances is odd, normal-mode noise currents having
opposite directions flow in the first X condenser C1 and the second
X condenser C2; therefore, the attenuation characteristics of the
noise filter can be improved. Moreover, in the noise filter
according to Embodiment 1 of the present invention, the first X
condenser C1 is situated at the power source side; however, the
position of the first X condenser is not limited thereto, and even
when the first X condenser C1 is situated at the electric-apparatus
load side, the attenuation characteristic of the noise filter can
be improved in a similar manner.
Embodiment 2
Next, a noise filter according to Embodiment 2 of the present
invention will be explained. FIG. 9 is a circuit diagram for
explaining a noise filter according to Embodiment 2 of the present
invention; FIG. 10 is a perspective view schematically illustrating
the noise filter according to Embodiment 2 of the present
invention. In FIGS. 9 and 10, the noise filter according to
Embodiment 2 of the present invention is provided with the first X
condenser C1, as a first X condenser, the second X condenser C2, as
a second X condenser, and a third X condenser C3, as a third X
condenser. The first, second, and third X condensers C1, C2, and C3
are connected in parallel with one another and form a filter
circuit.
The noise filter configured in such a manner as described above is
inserted between a power source and an electric apparatus or
between the electric apparatus and a load of the electric apparatus
and attenuates noise generated by the electric apparatus.
The first wiring lead 3 connects the terminal 1, one of the
terminals of the first X condenser C1, with the terminal 2, one of
the terminals of the second X condenser C2; the second wiring lead
6 connects the terminal 4, the other one of the terminals of the
first X condenser C1, with the terminal 5, the other one of the
terminals of the second X condenser C2. The first wiring lead 3 and
the second wiring lead 6 are arranged in such a way as to intersect
each other once. As described above, the noise filter configured in
such a manner is inserted between the power source and the electric
apparatus or between the electric apparatus and the load of the
electric apparatus so as to attenuate noise generated by the
electric apparatus. As illustrated in FIG. 2, the first and second
X condensers C1 and C2 each denote a metalized film condenser that
is utilized in a noise filter, in general, and are arranged in such
a way as to be parallel to each other.
The third X condenser C3, which is a condenser other than the first
and second X condensers C1 and C2, is connected in parallel with
each of the first and second X condensers C1 and C2. The first
wiring lead 3 and the second wiring lead 6 are arranged in such a
way as to intersect each other once. As illustrated in FIG. 10, the
first, second, and third X condensers C1, C2, and C3 each denote a
metalized film condenser that is utilized in a noise filter, in
general, and are arranged in such a way as to be parallel to one
another. The other configurations are the same as those in
Embodiment 1. As illustrated in FIGS. 9 and 10, it is assumed that
the noise source V1 exists at the electric apparatus side.
The number of intersections between the first wiring lead 3 and the
second wiring lead 6 is not limited to one; it is only necessary to
be an odd number. There may be provided an X condenser, which is
further another X condenser that is connected in parallel with each
of the first through third X condensers C1, C2, and C3.
In the noise filter according to Embodiment 2 of the present
invention, the mechanism of improving the attenuation
characteristics of the noise filter is basically the same as the
mechanism in the noise filter according to Embodiment 1. FIG. 11 is
an explanatory diagram representing current paths through which
normal-mode noise currents flow in the X condensers in the noise
filter according to Embodiment 2 of the present invention; there is
illustrated current paths through which normal-mode noise currents
generated by the noise source V1 flow in the first through third X
condensers C1, C2, and C3. FIG. 12 is a perspective view
schematically illustrating the current paths through which the
normal-mode noise currents flow in the X condensers and the
magnetic fluxes generated by the normal-mode currents in the noise
filter according to Embodiment 2 of the present invention.
In FIGS. 11 and 12, i1 denotes a normal-mode noise current that
flows in the first X condenser C1; i2 denotes a normal-mode noise
current that flows in the second X condenser C2; furthermore, i3
denotes a normal-mode noise current that flows in the third X
condenser C3. In FIG. 12, .PHI.1, .PHI.2, and .PHI.3 denote
magnetic flux generated by the first X condenser C1, magnetic flux
generated by the second X condenser C2, and magnetic flux generated
by the third X condenser C3, respectively. In addition, .PHI.13'
denotes magnetic flux obtained by combining the magnetic fluxes,
out of the magnetic fluxes .PHI.1 and .PHI.3, that are interlinked
with the second X condenser C2; .PHI.2' denotes magnetic flux, out
of the magnetic fluxes .PHI.2, that are interlinked with the first
and second X condensers C1 and C2.
In FIGS. 11 and 12, the normal-mode noise currents i1 and i3 having
the same direction flow in the first X condenser C1 and the third X
condenser C3; therefore, the direction of the magnetic flux .PHI.1
is the same as that of the magnetic flux .PHI.3 (in that direction,
the magnetic flux .PHI.1 and the magnetic flux .PHI.3 strengthen
each other). In contrast, because the respective wiring leads for
connecting the first X condenser C1 and the second X condenser C2
intersect each other once, a normal-mode noise current flows in the
second X condenser C2 in a direction opposite to the directions of
normal-mode noise currents in the first X condenser C1 and the
third X condenser C3; thus, the direction of the magnetic flux
.PHI.13' is opposite to that of the magnetic flux .PHI.2' (in those
directions, the magnetic flux .PHI.13' and the magnetic flux
.PHI.2' cancel each other).
As a result, the respective magnetic coupling instances among the
first through third X condensers C1, C2, and C3 can be suppressed.
Accordingly, in the noise filter configured with three or more X
condensers that are connected in parallel with one another, when
the direction of a normal-mode noise current in at least one X
condenser is made to be opposite to the directions of normal-mode
noise currents in the other X condensers, magnetic coupling
instances among the X condensers can be suppressed.
Due to the foregoing operational principle, as is the case with the
noise filter according to Embodiment 1, magnetic coupling instances
among the X condensers can be suppressed also in the noise filter
according to Embodiment 2 of the present invention; thus, the
noise-mode attenuation effect of the noise filter can be
improved.
In Embodiment 2, the third X condenser C3 is situated at the power
source side and the second X condenser C2 is situated at the
electric apparatus side; however, the arrangement of the X
condensers is not limited thereto. Even when the second X condenser
C2 is situated at the power source side and the third X condenser
C3 is situated at the electric apparatus side, the attenuation
characteristics of the noise filter can also be improved. Moreover,
in the noise filter according to Embodiment 2, the third X
condenser C3 is situated at the power source side and the second X
condenser C2 is situated at the electric apparatus side; however,
the arrangement of the X condensers is not limited thereto. Even
when the second X condenser C2 is situated at the load side and the
third X condenser C3 is situated at the electric apparatus side,
the attenuation characteristics of the noise filter can also be
improved. Furthermore, in the noise filter according to Embodiment
2, the third X condenser C3 is situated at the power source side
and the second X condenser C2 is situated at the electric apparatus
side; however, the arrangement of the X condensers is not limited
thereto. Even when the second X condenser C2 is situated at the
electric apparatus side and the third X condenser C3 is situated at
the load side, the attenuation characteristics of the noise filter
can also be improved.
Embodiment 3
Next, a noise filter according to Embodiment 3 of the present
invention will be explained. FIG. 13 is a circuit diagram for
explaining a noise filter according to Embodiment 3 of the present
invention; FIG. 14 is a perspective view schematically illustrating
the noise filter according to Embodiment 3 of the present
invention. As illustrated in FIGS. 13 and 14, the noise filter
according to Embodiment 3 of the present invention is provided with
a filter circuit including the first X condenser C1, as a first X
condenser, the second X condenser C2, as a second X condenser, a
first coil L1, and a second coil L2. The first coil L1 and the
second coil L2 form a common-mode choke coil. The first and second
X condensers C1 and C2 and the common-mode choke coil including the
first and second coils L1 and L2 form a filter circuit.
The noise filter configured in such a manner as described above is
inserted between a power source and an electric apparatus or
between the electric apparatus and a load of the electric apparatus
and attenuates noise generated by the electric apparatus. As
illustrated in FIGS. 13 and 14, it is assumed that the noise source
V1 exists at the electric apparatus side.
A first wiring lead 8 connects one terminal 1 of the first X
condenser C1 with one terminal 7 of the second coil L2; a second
wiring lead 10 connects the other terminal 2 of the first X
condenser C1 with one terminal 9 of the first coil L1. The first
wiring lead 8 and the second wiring lead 10 are arranged in such a
way as to intersect each other once. One terminal 4 of the second X
condenser C2 is connected with the other terminal 12 of the second
coil L2; the other terminal 5 of the second X condenser C2 is
connected with the other terminal 11 of the first coil L1.
The number of intersections between the first wiring lead 8 and the
second wiring lead 10 is not limited to one; it is only necessary
to be an odd number.
In the noise filter according to Embodiment 3 of the present
invention, the mechanism of improving the attenuation
characteristics of the noise filter is the same as the mechanism in
the noise filter according to Embodiment 1. FIG. 15 is an
explanatory diagram representing current paths through which
normal-mode noise currents flow in the X condensers in the noise
filter according to Embodiment 3 of the present invention. FIG. 16
is a perspective view schematically illustrating the current paths
through which the normal-mode noise currents flow in the X
condensers and the magnetic fluxes generated by the normal-mode
currents in the noise filter according to Embodiment 3 of the
present invention.
In FIGS. 15 and 16, i1 denotes a normal-mode noise current that
flows in the first X condenser C1; i2 denotes a normal-mode noise
current that flows in the second X condenser C2. In FIG. 16,
.PHI.1, .PHI.2, .PHI.1', and .PHI.2' denote magnetic flux generated
by the first X condenser C1, magnetic flux generated by the second
X condenser C2, magnetic flux, out of the magnetic flux .PHI.1,
that is interlinked with the second X condenser C2, and magnetic
flux, out of the magnetic flux .PHI.2, that is interlinked with the
first X condenser C1, respectively.
In FIGS. 15 and 16, the wiring leads for connecting the first X
condenser C1 with the common-mode choke coil including the first
and second coils L1 and L2 intersect each other once so that as is
the case with the noise filter according to Embodiment 1,
respective normal-mode noise currents having opposite directions
flow in the first and second X condensers C1 and C2. The respective
directions of the magnetic flux .PHI.1 and the magnetic flux .PHI.2
are opposite to each other (in those directions, the magnetic flux
.PHI.1 and the magnetic flux .PHI.2 cancel each other). As a
result, the magnetic coupling between the first X condenser C1 and
the second X condenser C2 can be suppressed.
FIG. 17 is a characteristic graph representing the noise
attenuation characteristics of the noise filter according to
Embodiment 3 of the present invention; the abscissa denotes the
frequency and the ordinate denotes the gain (the noise attenuation
amount). The smaller the value of the gain is, the larger the noise
attenuation amount is. In FIG. 17, a broken line A represents the
noise attenuation characteristics of a noise filter (a conventional
noise filter) at a time when the wiring leads for connecting the
first X condenser C1 with the common-mode choke coil including the
first and second coils L1 and L2 do not intersect each other
odd-number times. A solid line B represents the noise attenuation
characteristics of the noise filter according to Embodiment 3 of
the present invention. As evident from FIG. 17, it can be
ascertained that the noise attenuation characteristics of the noise
filter according to Embodiment 3 of the present invention is
improved in comparison with those of the conventional noise
filter.
As described above, even in the case of a configuration in which
the common-mode choke coil including the first and second coils L1
and L2 is connected between the first X condenser C1 and the second
X condenser C2, when the respective wiring leads for connecting the
first X condenser C1 and the common-mode choke coil intersect each
other once, it is made possible to suppress the magnetic coupling
between the X condensers; thus, the normal-mode attenuation
characteristics of the noise filter can be improved.
In the case of the noise filter according to Embodiment 3 of the
present invention, there has been illustrated a configuration in
which the respective wiring leads for connecting the first X
condenser C1 and the common-mode choke coil including the first and
the second coils L1 and L2 intersect each other once; however, the
number of intersection instances is not limited thereto and the
respective wiring leads may intersect each other once or more times
as long as the number of intersection instances is an odd number.
Moreover, the respective wiring leads for connecting the second X
condenser C2 and the common-mode choke coil including the first and
the second coils L1 and L2 may intersect each other odd-number
times; even in this case, the attenuation effect of the noise
filter can be improved.
In the case of the noise filter according to Embodiment 3, there
has been illustrated a configuration in which the common-mode choke
coil including the first and second coils L1 and L2 is utilized;
however, the present invention is not limited thereto and the first
and second choke coils may be formed of respective normal-mode
choke coils. The normal-mode inductance value of a common-mode
choke coil is a low value, in general; therefore, when two
normal-mode choke coils are utilized, the attenuation effect can be
obtained at a low frequency range.
Furthermore, in the noise filter according to Embodiment 3, the
first X condenser C1 is situated at the power source side and the
second X condenser C2 is situated at the electric apparatus side;
however, the arrangement of the X condensers is not limited
thereto. Even when the second X condenser C2 is situated at the
power source side and the first X condenser C1 is situated at the
electric apparatus side, the attenuation characteristics of the
noise filter can also be improved. Moreover, in the noise filter
according to Embodiment 3, the first X condenser C1 is situated at
the power source side and the second X condenser C2 is situated at
the electric apparatus side; however, the arrangement of the X
condensers is not limited thereto. Even when the second X condenser
C2 is situated at the load side and the first X condenser C1 is
situated at the electric apparatus side, the attenuation
characteristics of the noise filter can also be improved.
Furthermore, in the noise filter according to Embodiment 3, the
first X condenser C1 is situated at the power source side and the
second X condenser C2 is situated at the electric apparatus side;
however, the arrangement of the X condensers is not limited
thereto. Even when the second X condenser C2 is situated at the
electric apparatus side and the first X condenser C1 is situated at
the load side, the attenuation characteristics of the noise filter
can also be improved.
Embodiment 4
Next, a noise filter according to Embodiment 4 of the present
invention will be explained. FIG. 18 is a circuit diagram for
explaining a noise filter according to Embodiment 4 of the present
invention; FIG. 19 is a perspective view schematically illustrating
the noise filter according to Embodiment 4 of the present
invention. As illustrated in FIGS. 18 and 19, the noise filter
according to Embodiment 4 of the present invention is provided with
a filter circuit including the first X condenser C1, as a first
condenser, the second X condenser C2, as a second condenser, the
third X condenser C3, as a third condenser, and a common-mode choke
coil including the first coil L1 and the second coil L2.
The noise filter configured in such a manner as described above is
inserted between a power source and an electric apparatus or
between the electric apparatus and a load of the electric
apparatus; the filter circuit attenuates noise in a main circuit.
As illustrated in FIGS. 18 and 19, it is assumed that the noise
source V1 exists at the electric apparatus side.
A first wiring lead 8 connects one terminal 1 of the first X
condenser C1 with one terminal 7 of the second coil L2; a second
wiring lead 10 connects the other terminal 2 of the first X
condenser C1 with one terminal 9 of the first coil L1. The first
wiring lead 8 and the second wiring lead 10 are arranged in such a
way as to intersect each other once. One terminal 4 of the second X
condenser C2 is connected with the other terminal 12 of the second
coil L2; the other terminal 5 of the second X condenser C2 is
connected with the other terminal 11 of the first coil L1. The
third X condenser C3 is connected in parallel with the second X
condenser C2.
The number of intersections between the first wiring lead 8 and the
second wiring lead 10 is not limited to one; it is only necessary
to be an odd number.
At first, the current path of a normal-mode noise current will be
explained. FIG. 20 is an explanatory diagram representing current
paths through which normal-mode noise currents flow in X condensers
in the noise filter according to Embodiment 4 of the present
invention; FIG. 21 is a perspective view schematically illustrating
the current paths through which the normal-mode noise currents flow
in the X condensers and the magnetic fluxes generated by the
normal-mode currents in the noise filter according to Embodiment 4
of the present invention.
In FIGS. 20 and 21, i1 denotes a normal-mode noise current that
flows in the first X condenser C1; i2 denotes a normal-mode noise
current that flows in the second X condenser C2; i3 denotes a
normal-mode noise current that flows in the third X condenser C3.
In FIG. 21, .PHI.1, .PHI.2, and .PHI.3 denote magnetic flux
generated by the first X condenser C1, magnetic flux generated by
the second X condenser C2, and magnetic flux generated by the third
X condenser C3, respectively. In addition, .PHI.13' denotes
magnetic flux obtained by combining the magnetic fluxes, out of the
magnetic fluxes Dl and .PHI.3, that are interlinked with the second
X condenser C2; .PHI.2' denotes magnetic flux, out of the magnetic
fluxes .PHI.2, that are interlinked with the first and second X
condensers C1 and C2.
In FIGS. 20 and 21, the normal-mode noise currents i1 and i3 having
the same direction flow in the first X condenser C1 and the third X
condenser C3; therefore, the direction of the magnetic flux .PHI.1
is the same as that of the magnetic flux .PHI.3 (in that direction,
the magnetic flux .PHI.1 and the magnetic flux .PHI.3 strengthen
each other). In contrast, because the respective wiring leads for
connecting the first X condenser C1 with the common-mode choke coil
including the first and second choke coils L1 and L2 intersect each
other once, a normal-mode noise current flows in the second X
condenser C2 in a direction opposite to the directions of
normal-mode noise currents in the first X condenser C1 and the
third X condenser C3; thus, the direction of the magnetic flux
.PHI.3' is opposite to that of the magnetic flux .PHI.2' (in those
directions, the magnetic flux .PHI.3' and the magnetic flux .PHI.2'
cancel each other). As a result, the respective magnetic coupling
instances among the first through third X condensers C1, C2, and C3
can be suppressed.
The noise filter according to Embodiment 4 is configured in such a
way that the respective wiring leads for connecting the first X
condenser C1 and the common-mode choke coil including the first and
the second coils L1 and L2 intersect each other once; however, the
number of intersection instances is not limited thereto and the
respective wiring leads may intersect each other once or more times
as long as the number of intersection instances is an odd number.
Moreover, even when the noise filter according to Embodiment 4 is
configured in such a way that the respective wiring leads for
connecting the second X condenser C2 and the common-mode choke coil
including the first and the second coils L1 and L2 intersect each
other odd-number times; the attenuation effect of the noise filter
can be improved.
Embodiment 5
Next, a noise filter according to Embodiment 5 of the present
invention will be explained. FIG. 22 is a circuit diagram for
explaining a noise filter according to Embodiment 5 of the present
invention; FIG. 23 is a perspective view schematically illustrating
the noise filter according to Embodiment 5 of the present
invention. As illustrated in FIGS. 22 and 23, the noise filter
according to Embodiment 5 of the present invention is provided with
a filter circuit including the first X condenser C1, as a first
condenser, the second X condenser C2, as a second condenser, the
third X condenser, as a third condenser, and a common-mode choke
coil including the first coil L1 and the second coil L2. In
addition, the noise filter according to Embodiment 5 is configured
in such a way that the respective wiring leads for connecting the
first X condenser C1 with the third X condenser C3 intersect each
other odd-number times.
In FIGS. 22 and 23, because the respective wiring leads for
connecting the first X condenser C1 with the third X condenser C3
intersect each other once, respective normal-mode noise currents
having opposite directions flow in the first and third X condensers
C1 and C3. Accordingly, the respective directions of magnetic
fluxes generated by those normal-mode noise currents are opposite
to each other (in those directions, the respective magnetic fluxes
cancel each other). As a result, the respective magnetic coupling
instances among the first through third X condensers C1, C2, and C3
can be suppressed. In the case where an X condenser is further
connected with the second X condenser C2 or the third X condenser
C3, the respective wiring leads for connecting that X condenser
with the second X condenser C2 or the third X condenser C3 are made
to intersect each other odd-number times, so that the magnetic
coupling can be suppressed.
The noise filter according to Embodiment 5 is configured in such a
manner that the respective wiring leads for connecting the first X
condenser C1 with the third X condenser C3 intersect each other
once; however, the number of intersection instances is not limited
thereto, and the respective wiring leads may intersect each other
once or more times as long as the number is odd.
In each of Embodiments 4 and 5, a single common-mode choke coil is
configured with the first and second coils L1 and L2; however, the
present invention is not limited thereto and it may be allowed that
two or more common-mode choke coils configured in the same manner
are provided. FIG. 24 is a circuit diagram representing a noise
filter that is a variant example of the noise filter according to
Embodiment 5 of the present invention and in which two common-mode
choke coils are utilized; FIG. 25 is a perspective view
schematically illustrating the noise filter that is a variant
example of the noise filter according to Embodiment 5 of the
present invention. Alternatively, it may be allowed that each of
the first and second coils L1 and L2 is formed of a normal-mode
choke coil. The normal-mode inductance value of a common-mode choke
coil is a low value, in general; therefore, when two common-mode
choke coils or two normal-mode choke coils are utilized, the
attenuation effect can be obtained at a low frequency range.
Moreover, in each of Embodiments 4 and 5, the third X condenser C3
is situated at the power source side and the second X condenser C2
is situated at the electric apparatus side; however, the
arrangement of the X condensers is not limited thereto. Even when
the second X condenser C2 is situated at the power source side and
the third X condenser C3 is situated at the electric apparatus
side, the attenuation characteristics of the noise filter can also
be improved. Moreover, in each of Embodiments 4 and 5, the third X
condenser C3 is situated at the power source side and the second X
condenser C2 is situated at the electric apparatus side; however,
the arrangement of the X condensers is not limited thereto. Even
when the second X condenser C2 is situated at the load side and the
third X condenser C3 is situated at the electric apparatus side,
the attenuation characteristics of the noise filter can also be
improved. Still moreover, in each of Embodiments 4 and 5, the third
X condenser C3 is situated at the power source side and the second
X condenser C2 is situated at the electric apparatus side; however,
the arrangement of the X condensers is not limited thereto. Even
when the second X condenser C2 is situated at the electric
apparatus side and the third X condenser C3 is situated at the load
side, the attenuation characteristics of the noise filter can also
be improved.
In each of Embodiments 1 through 5, the constituent components of
the noise filter are connected by wiring leads; however, the
present invention is not limited thereto and it may be allowed that
the constituent components are mounted on a circuit board and the
wiring leads are formed of circuit-board strip conductors.
Furthermore, in each of Embodiments 1 through 5, the constituent
components of the noise filter are connected by wiring leads;
however, the present invention is not limited thereto and it may be
allowed that the constituent components of the noise filter are
connected by conductive wires such as bus bars or lead wires.
In the scope of the present invention, the embodiments thereof can
appropriately be modified or omitted.
Each of the foregoing noise filters according to respective
Embodiments of the present invention is the one in which at least
any one of the following inventions is put into practice. (1) A
noise filter comprising a first film condenser and a second film
condenser,
wherein the first film condenser and the second film condenser are
arranged at a distance in which they are magnetically coupled with
each other and are connected in parallel with each other by a first
wiring lead for connecting one terminal of the first film condenser
with one terminal of the second film condenser and a second wiring
lead for connecting the other terminal of the first film condenser
with the other terminal of the second film condenser, and
wherein the first wiring lead and the second wiring lead are
arranged in such a way as to intersect each other odd-number times.
(2) A noise filter comprising a first film condenser, a second film
condenser, a first coil, and a second coil,
wherein the first film condenser and the second film condenser are
arranged at a distance in which they are magnetically coupled with
each other,
wherein there are provided a first wiring lead for connecting one
terminal of the first film condenser with one terminal of the
second coil and a second wiring lead for connecting the other
terminal of the first film condenser with one terminal of the first
coil,
wherein one terminal of the second film condenser is connected with
the other terminal of the second coil,
wherein the other terminal of the second film condenser is
connected with the other terminal of the first coil, and
wherein the first wiring lead and the second wiring lead are
arranged in such a way as to intersect each other odd-number times.
(3) The noise filter according to (2), wherein each of the first
coil and the second coil is formed of a normal-mode choke coil. (4)
The noise filter according to (2), wherein the first coil and the
second coil form a common-mode choke coil. (5) A noise filter
comprising three or more film condensers including a first film
condenser and a second film condenser,
wherein the first film condenser and the second film condenser are
arranged at a distance in which they are magnetically coupled with
each other and are connected in parallel with each other by a first
wiring lead for connecting one terminal of the first film condenser
with one terminal of the second film condenser and a second wiring
lead for connecting the other terminal of the first film condenser
with the other terminal of the second film condenser,
wherein each of the film condensers other than the first film
condenser and the second film condenser is connected in parallel
with the first film condenser and the second film condenser,
and
wherein the first wiring lead and the second wiring lead are
arranged in such a way as to intersect each other odd-number times.
(6) A noise filter comprising three or more film condensers
including a first film condenser and a second film condenser, a
first coil, and a second coil,
wherein the first film condenser and the second film condenser are
arranged at a distance in which they are magnetically coupled with
each other,
wherein there are provided a first wiring lead for connecting one
terminal of the first film condenser with one terminal of the
second coil and a second wiring lead for connecting the other
terminal of the first film condenser with one terminal of the first
coil,
wherein one terminal of the second film condenser is connected with
the other terminal of the second coil,
wherein the other terminal of the second film condenser is
connected with the other terminal of the first coil,
wherein each of the film condensers other than the first film
condenser and the second film condenser is connected in parallel
with the first film condenser and the second film condenser,
and
wherein at least one pair of wiring leads among the first and
second wiring leads and respective pairs of wiring leads for
connecting the film condensers in parallel with each other
intersect each other odd-number times. (7) The noise filter
according to (6), wherein each of the first coil and the second
coil is formed of a normal-mode choke coil. (8) The noise filter
according to (6), wherein the first coil and the second coil form a
common-mode choke coil. (9) A noise filter comprising a first film
condenser, a second film condenser, a third film condenser, a first
coil, a second coil, a third coil, and a fourth coil,
wherein the first film condenser, the second film condenser, and
the third film condenser are arranged at distances in which they
are magnetically coupled with one another,
wherein there are provided a first wiring lead for connecting one
terminal of the first film condenser with one terminal of the first
coil, a second wiring lead for connecting the other terminal of the
first film condenser with one terminal of the second coil, a third
wiring lead for connecting one terminal of the third film condenser
with the other terminal of the first coil, a fourth wiring lead for
connecting the other terminal of the third film condenser with the
other terminal of the second coil, a fifth wiring lead for
connecting one terminal of the third film condenser with one
terminal of the third coil, a sixth wiring lead for connecting the
other terminal of the third film condenser with one terminal of the
fourth coil, a seventh wiring lead for connecting one terminal of
the second film condenser with the other terminal of the third
coil, and an eighth wiring lead for connecting the other terminal
of the second film condenser with the other terminal of the fourth
coil, and
wherein in at least one of the respective wiring pairs between the
first wiring lead and the second wiring lead, the third wiring lead
and the fourth wiring lead, the fifth wiring lead and the sixth
wiring lead, and the seventh wiring lead and the eighth wiring
lead, the wiring leads intersect each other odd-number times. (10)
The noise filter according to (9), wherein each of the first coil,
the second coil, the third coil, and the fourth coil is formed of a
normal-mode choke coil. (11) The noise filter according to (9),
wherein each of the respective pairs between the first coil and the
second coil and between the third coil and the fourth coil forms a
common-mode choke coil. (12) The noise filter according to (2),
wherein the one and the other terminals of the first film condenser
are connected to a power source, and
wherein the one and the other terminals of the second film
condenser are connected to an electric apparatus. (13) The noise
filter according to (2), wherein the one and the other terminals of
the first film condenser are connected to an electric apparatus,
and
wherein the one and the other terminals of the second film
condenser are connected to a power source. (14) The noise filter
according to (2), wherein the one and the other terminals of the
first film condenser are connected to an electric apparatus,
and
wherein the one and the other terminals of the second film
condenser are connected to a load of an electric apparatus. (15)
The noise filter according to (2), wherein the one and the other
terminals of the first film condenser are connected to a load of an
electric apparatus, and
wherein the one and the other terminals of the second film
condenser are connected to an electric apparatus. (16) The noise
filter according to (1), wherein the filter circuit is mounted on a
circuit board, and
wherein at least the first and second wiring leads are each formed
of a circuit-board strip conductor. (17) The noise filter according
to (1), wherein at least the first and second wiring leads are each
formed of a bus bar. (18) The noise filter according to (1),
wherein at least the first and second wiring leads are each formed
of a conductive wire such as a lead wire.
INDUSTRIAL APPLICABILITY
The present invention can be utilized in the field of an electric
apparatus such as an AC/DC converter or an inverter or in the field
of a vehicle such as an automobile in which the foregoing electric
apparatus is mounted.
DESCRIPTION OF REFERENCE NUMERALS
C1: 1st across-the-line condenser (1st X condenser) C1: 2nd
across-the-line condenser (2nd X condenser) C3: 3rd across-the-line
condenser (3rd X condenser) L1: 1st coil L2: 2nd coil V1: noise
source
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